The present invention relates to a primer composition for coating polyolefin-backed pressure sensitive tapes to improve the bond between the polyolefin substrate and the adhesive.
Polyolefins, particularly polypropylene, are useful as a backing material for pressure sensitive tape. However, polyolefins typically have a very low surface energy making it difficult to securely apply a coating such as a pressure sensitive adhesive (PSA) to the surface of the polyolefin substrate. Traditionally, the surface of the polyolefin substrate is treated with, for example, corona discharge to increase the surface energy of the substrate. This treatment improves the bond between adhesive and substrate, but only to a limited degree.
Chlorinated polyolefin primer coatings have also been employed in polypropylene backed pressure sensitive adhesive tape. While these primer coatings adhere well to the polypropylene substrate, they do not bond well to the pressure sensitive adhesives. Accordingly, it is desirable to provide a polypropylene backed pressure sensitive adhesive tape which exhibits improved bonding between the polypropylene substrate and the pressure sensitive adhesive.